When the ALTER TABLE statement adds a column to the table, it initializes the column's values to missing in all rows of the table. Use the UPDATE statement to add values to the new column (s).

How to Create a Table From Query Results in Microsoft SQL. If your business uses relational databases to store data, you may have used a SQL SELECT clause to create new tables from query results.

You add a column for the combined values and then group if you want to combine those values further into a single record.